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Ms. Jennifer S. Lindhal Page 3 <br /> June 8, 2016 <br /> In accordance with the letter dated April 30, 2010 (copy attached) from the Colorado Division <br /> of Reclamation, Mining, and Safety ("DRMS"), all sand and gravel mining operators must comply with <br /> the requirements of the Colorado Reclamation Act and the Mineral Rules and Regulations for the <br /> protection of water resources. The April 30, 2010 letter from DRMS requires that you provide <br /> information to DRMS to demonstrate you can replace long term injurious stream depletions that <br /> result from mining related exposure of ground water. The DRMS letter identified four approaches to <br /> satisfy this requirement. <br /> In accordance with approach nos. 1 and 3, you have indicated that a bond has been obtained <br /> for each site that can cover the cost of lining of each site to prevent the exposure of ground water. <br /> The current bond amount for each pit is shown in Table B below. <br /> TABLE B - DRMS Bonding <br /> Site Name DBMS # Bond Amount <br /> Morton Lakes M2008-082 $202,000 <br /> Depletions <br /> The depletions resulting from evaporation, water lost in product, dust control and first fill are <br /> shown in Table C below: <br /> _TABLE C —DEPLETIONS SUMMARY <br /> Evaporation Lost in Dust I First Fit[ Total <br /> Total <br /> j Site Name Year Losses Product Control ! Lagged i <br /> I (ac-ft) (ac-ft) lac-ft) {ac-ft) <br /> � (ac-ft) (ac-ft) <br /> 2016 0.0 0.0 0.0 0 0.0 0.0 <br /> Holton Lakes <br /> 2017 4.0 21.63 8.4 0 34.0 34.0 <br /> 2016 16.89 28.12 10.82 0 ? 55.8 52.4 <br /> Morton Lakes <br /> 2017 44.52 22.53 5.96 242 315.0 313.5 <br /> Total 65.51 72.3' 25.2 242 404.7 399.9 <br /> " Based on 955,000 tons of mined material for 2016 and 1,500,000 tons of mined material for 2017 <br /> The Applicant proposed to replace evaporation from exposed ground water at these sites <br /> based upon evaporation atlases in NOAA Technical Report NWS 33 and the SEO monthly distribution <br /> factors for sites below 6,500 feet, as shown in attached Table 1. Gross annual evaporation at these <br /> gravel pit locations is estimated to be 44.27 inches per year. Net evaporation is defined as gross <br /> evaporation less the consumptive use of water by vegetation that naturally occurred at the site prior to <br /> construction of the pit. The historical consumptive use was assumed to be equal to the effective <br /> precipitation, which was estimated based on the data from the Fort Lupton 2SE (ID 3027, record 1950- <br />